Step down voltage
A transformer is built from coiling wires around an iron core. The output wire is wrapped around the core as well, but the number of coils is reduced. By reducing the number of coils, the technician is able to significantly inhibit the flow of voltage coming off the output wire.
Types
The technician or builder will determine the type of transformer to build. There are liquid insulated and gas-cooled transformers to select from. Liquid-insulated transformers utilize conventional mineral oil, hydrocarbons or silicons as a cooling medium. The technician will build a liquid-insulated transformer for better overload capacity, especially if the coils need to be cooled quickly. The life span of a liquid-insulated transformer is higher than a dry transformer. However, the technician will build a shielding trough to prevent fluids from leaking (liquids mediums are more fire prone and might explode). If the transformer is built indoors (600 volts or less), then the technician or engineer will select a dry-insulation design for the transformer. Outdoor installations tend to be liquid-insulated transformers because of the higher-voltage capacity in liquid mediums.
Liquid insulation
Liquid-insulation transformers are made of enameled wire. Cellulose paper (made from sulfate wood mash) containing a di-electric liquid is placed inside of the liquid-insulation transformer. The coil arrangement (with iron core) is mounted in the liquid-containment tank, with leads connected. The liquid medium is funneled into the containment tank. Additional leads are added to the containment tank to provide an electric current to the coils (moisture is removed). Heated dielectric liquid is poured into the containment tank. Throughout the liquid insulation installation, a vacuum is used to help remove moisture. Eventually, the containment tank is sealed shut. There is a bit of space allowed between the liquid and the cover of the containment tank for thermal cycling (expansion/contraction).
Dry insulation
Dry-transformer windings are insulated by preheating the conductor coils, dipping the conductor coils in a varnish and then curing the conductor coils in an oven (baking). Ducts are installed in the transformer windings. Cool air flows through the ducts while heat is dispersed from the electrical discharges of the transformer.
Tags: containment tank, conductor coils, into containment, into containment tank, iron core, liquid-insulated transformer
